On the Cover: Top: As Huygens floated down through Titan’s atmosphere, it captured these 30 images from altitudes of 13 to 8 kilometers (9 to 5 miles). Details are visible down to about 20 meters across, and the images cover an area 30 kilometers (about 19 miles) wide.

Bottom: A mountainous coastline marks the landscape near Huygens’ landing site, as seen in this mosaic. Dark channels drain into a major river below. To terrestrial eyes, this looks like an aerial photo of a scenic lakeshore, but on Titan, water behaves like rock and hydrocarbons flow like water.ESA / NASA / University of Arizona